Voters deserted the Conservatives during a punishing year for the party as it dropped almost one-fifth of its electoral support, The Independent’s latest poll of polls can disclose.

As 2013 begins, the Tories’ popular support has yet to recover from a slide that began during a troubled spring, including George Osborne’s “omnishambles” Budget, leaving Labour with ratings that, if repeated in a General Election, could be enough to put Ed Miliband in Downing Street with a majority of more than 100. To add to the new year gloom for the Prime Minister, the UK Independence Party achieved record levels of popularity.

The poll underlines the challenges facing David Cameron as he attempts to seize the political initiative in the new year with a long-awaited speech laying out his vision of Britain’s place in Europe.

A weighted average of last month’s polls puts the Conservatives on 32 per cent (down seven points since December 2011) while Labour is on 41 per cent (up three). The Liberal Democrats’ support has held up better than their coalition partners this year (now 11 per cent, down one), but the party began 2012 at a low ebb and ends the year struggling to reach double figures. It is now in danger of being overtaken by Ukip, which polled an average of eight per cent, compared with three per cent at the turn of last year.

John Curtice, professor of politics at Strathclyde University, who calculated the averages, said the turning-point for the Tories had been in March/April when the Tory rating fell below 35 per cent and has not recovered.

The party’s support appears to have been hit by the ill-received Budget as well as controversies including the handling of the petrol tankers’ strike and confusion over the deportation of the cleric Abu Qatada.

Alarm is also growing in Conservative ranks about the steady advance of Ukip both in the polls and in by-elections (the party came second in the contest in Rotherham last month and third in Corby in November).

Prof Curtice said that Ukip was disproportionately attracting support from Tories and had become “a convenient and acceptable vehicle of protest for disillusioned Conservative voters”.

Mr Cameron and Liberal Democrat leader Nick Clegg will shortly move to reinvigorate the Coalition by setting out plans for its next two years in office as well as listing its achievements since its creation in May 2010.

However, the Coalition’s immediate fortunes could depend on whether the recent tentative economic recovery – accompanied by falling unemployment – continues into 2013. Its problems in winning back voters could be exacerbated by the publication of the next Comprehensive Spending Review, which is likely to extend austerity measures.

Labour has edged up slowly in support over the last 12 months and has been consistently around the 40 per cent it needs for a convincing election victory for most of the year.

It will face a key test in May in elections to English shire counties. Labour fared disastrously the last time the seats were contested in 2009, so its performance will be a measure of whether it is rebuilding support in areas alienated by Gordon Brown’s government.